156557780657 has 2 divisors, whose sum is σ = 156557780658. Its totient is φ = 156557780656.

The previous prime is 156557780581. The next prime is 156557780663. The reversal of 156557780657 is 756087755651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83266296481 + 73291484176 = 288559^2 + 270724^2 .

It is an emirp because it is prime and its reverse (756087755651) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-156557780657 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 156557780657.

It is not a weakly prime, because it can be changed into another prime (156557780677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78278890328 + 78278890329.

It is an arithmetic number, because the mean of its divisors is an integer number (78278890329).

Almost surely, 2^156557780657 is an apocalyptic number.

It is an amenable number.

156557780657 is a deficient number, since it is larger than the sum of its proper divisors (1).

156557780657 is an equidigital number, since it uses as much as digits as its factorization.

156557780657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 61740000, while the sum is 62.

The spelling of 156557780657 in words is "one hundred fifty-six billion, five hundred fifty-seven million, seven hundred eighty thousand, six hundred fifty-seven".